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The enhancement effect on chromosomal aberrations via selective X-ray energy absorption by Cu atoms in GM05389 normal fibroblast cells containing non-labeled copper(II)-diacetyl-bis(N4-methyl- thiosemicarbazone)(Cu-ATSM) was examined. The amounts of Cu-ATSM taken into cells were detected by PIXE analysis, and it was clarified that the amount of Cu atoms taken into hypoxic cells was about 2 or 3-times higher compared to that into normoxic cells. Radioisotope analysis with 64Cu-ATSM showed that 8.7% of all Cu atoms taken into a whole cell was distributed to the nucleus, and the remaining atoms to the cytoplasm in the cells. Irradiation with monochromatic X rays (CuK-H X rays) having an energy just above the Cu K-shell absorption edge on the hypoxic cells induced high yield of chromosomal aberrations, compared to that with X rays (CuK-L X rays) having an energy just below the Cu K-shell absorption edge. Enhanced chromosomal aberrations caused by Cu K-shell ionization or excitation was clearly observed in this study.

Worker mandibles of two economically important subterranean pest termites, Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe), were investigated for their chemical properties and arrangement with special reference to the pigmentation and the particle-removing capacity. Both species deposited Mn in cutting edges of mandibles, and the deposition seemed to be closely related to the pigmentation and the hardening of the mandibles.The maximum openings of mandibles and maxillaes of C.formosanus workers were 0.45mm and 0.88mm, respectively, and the minimum gap between mandibles and maxillaes was 0.07mm.This theoretically results in that C.formosanus workers can remove particles with less than 1.9mm diameters if the particle is spherical in shape, coinciding well with the laboratory test results that 1.7-2.4mm sized particles were effective to prevent the invasion of workers of C.formosanus. In addition, workers of C.formosanus showed the maximum head width of approximately 1.2mm, indicating the particles with less than 2.9mm diameters are small enough to prevent the invasion of workers of C.formosanus. This also has no contradiction with the laboratory test results. These results strongly suggest that basic researches on termite mandibles can be the breakthrough to develop not only new termite control measures but also new biomimetic composite materials.

We attempted in-air-PIXE analysis of SPM using spot samples on a filter-tape mounted in an automated beta-ray absorption mass monitor. Al, Si, S, Fe and Zn etc., which are of interest for identifying the behavior and characteristics of SPM, were detected on the SPM spot samples on a glass-fiber filter-tape, but the peaks of these elements were nearly identical to those of blank glass-fiber filter-tape. As such, it was difficult to detect elements present in SPM from the X-ray spectra of the spot samples. On the other hand, in the case of a PTFE membrane filter-tape, the S peak was distinct and the Fe peak was also clear, and peaks for elements Al, Mn and Zn, etc., were also confirmed. Consequently, if a method for determining quantity is established, direct multi-elemental analysis by in-air-PIXE of high time-resolution SPM spot samples collected on a PTFE membrane filter-tape mounted in a SPM monitor will be possible.

Selective irradiation by an ionizing particle of a targeted cell organelle may disclose such mechanisms as signal transaction among cell organelles and cell-to-cell communication in the processes toward an endpoint observed. Bystander effect, existence of which has been clearly evidenced by application of the particle microbeam to biological experiments, suggests potential deviation from the conventional risk estimation at low particle fluence rates, such as in an environment of space radiation in International Space Station.To promote these studies we started the construction of a microbeam facility (named as SPICE) by using our HVEE Tandem accelerator (3.4 MeV proton and 5.1 MeV 4He2+). For our primary goal,"irradiation of cell organelle with a single praticle with a position resolution of 2 mum in a reasonable irradiation time", special features are considered. Usage of a triplet Q-magnet for focussing the beam to micrometer levels is an out standing feature compared to facilities of other institutes. Other features are almost similar to those of other institutes. Those are precise position control of a cell dish holder, design of the cell dish, data acquisition of microscopic image of a cell oraganelle (cell nucleus), data processing, reliable particle detection, soft and hard wares to integrate all these related data and system to control and irradiate a targeted spot with exactly determined number of particles.

Regrettably, a criticality accident occurred at a uranium conversion facility in Tokai-mura, Ibaraki, Japan, on 30 September, 1999. Radioactivities of 32P in urine, blood and bone samples of the victims who were severely exposed to neutrons were measured. 32P was induced in their whole bodies at the moment of the first nuclear excursion by the reaction 31P (n,gamma) 32P and 32S (n, p) 32P. A realistic biokinetic model was assumed as the exchange of 32P between extracellular fluid compartment and soft tissue compartment occurs only through intracellular compartment, and the model was used for preliminary calculations. Some acute excretion of 32P, caused by decomposition or elution of tissues which occurred at the time of the accident, may have happened in the victims' bodies in the first few days. The working hypotheses in the present work should initiate renewed discussion of 32P biokinetics.

Micro-beam scanning PIXE (micro-PIXE) and scanning transmisssion ion microscopy (STIM)were applied to measurement of one-year old seeding root from a Siebold's beech(Fagus crenata Blume) tree. The beech seedling root samples were collected at the centerpiece of the Shirakami-Sanchi World Heritage Area during October 2001. Target samples for micro-PIXE and STIM analyses were transverse sections from tip, midpoint and root of the beech seedling root. We focused shedding light on tree root. STIM images were similar to those generated using stereomicroscope and/or transmission microscopy. Real images in the form of elemental maps were obtained for nine elements: Na, Mg, Al, Si, P, S, Cl, K, and Ca. Of these typical elemental maps were Si and Ca, which were both, concentrated in the epidermis. Si was prominent in the tip, while Ca was prominent in the root.

Particle Induced X-ray Emission(PIXE)analysis is one of the analytical methods for elements. PIXE has high sensitivity, multi-elemental and non-destructive characteristics and the advantage of micro-beam scanning ability on the sample surface. In 1999, micro-beam scanning PIXE system was installed at the National Institute of Radiological Sciences (NIRS). The system allowed multi elemental mapping on 2mm x 2mm areas of small samples such as fish scales, small fish eyes, pollen etc. with a special resolution of about 1mu m with accelerated proton micro-beams produced by an electrostatic accelerator, Tandetron (Model 4117MC, High Voltage Engineering Europe Co.) and a micro-beam scanning system (Model OM2000, Oxford Micro Beams, Ltd.). Fine ring structure of a fish scale was observed with P and Ca maps. Pollen was examined to ability of the system to draw elemental distribution maps of singles cell. The distribution of elements in a thin section of Medaka eye was investigated in connection with Scanning Transmission Ion Microscopy (STIM).

In order to investigate the ingestion of iodine by human body and to know its content in organs, instrumental epithermal neutron activation analysis was used in conjunction with Compton suppression gamma-ray spectrometry by measuring the 128I short-lived nuclide. The interferences of 24Na and 38Cl induced from NaCl in a sample were reduced by factors of about 6 and 15 to 41 by employing the epithermal neutron activation and Compton suppression gamma-ray spectrometry, respectively. The present method can be used to determine iodine at levels higher than 11 ppb. It was applied to the determination of iodine of more than 35 ppb in various biological reference materials.

Background/Aims: The aim of this study was to investigate the relationship between trace metals and the prevalence of hepatocellular carcinoma (HCC) in patients with chronic hepatic cirrhosis caused by hepatitis C virus (HCV). Methods: We measured the contents of copper, iron, and zinc in HCC tissue (n=112), dysplastic nodules (n=7), and liver parenchyma in patients with (n=112) and without (12; 7 with grade F3 fibrosis, 5 with grade F4 fibrosis) HCC. Metals were quantified in thin-needle biopsy specimens using the particle-induced X-ray emission method (PIXE). Results: Copper level in liver parenchyma was higher in patients with HCC than in those without HCC (p

Artisanal/small-scale gold mining is one of the important livelihood for deprived people in many countries. The activity is expected to support people's life and activate local economy. However amalgamation method is common to recover gold in this type of mining, and due to this practice, mercury is being released into the natural environment. During the ore treatment process, miners uptake mercury not only by inhalation of the vapor but also by absorption of liquid mercury through the skin. In order to cope with health problems and environmental damages arising from the use of mercury, there should be coordination between national/local government, aid agencies and scientific institutes. In addition, the environmental education and risk communication are keys to mitigate the environmental damage by the miners. For such purpose, quick and precise trace element analysis as a base of discussion on occupational health risk is indispensable and our trial proved that PIXE is one of the most flexible and versatile system. In this paper examples of trial through a Japan-Philippines partnership will be presented.

Balance of essential elements in organisms might be changed by environmental stresses. Small teleost fish, Medaka, was burdened with X-ray irradiation (total dose: 17Gy) and salty water (70% NaCl of sea water). These stresses are not lethal dose. Essential elements in various organs in the fish were measured by PIXE method and compared with a control fish to determine the effect of two types of the burdens on the elemental contents. P, K, Ca and Br are examined in brain, eye, liver, ovary, spleen and intestine. P and K did not change their concentrations with both of the stresses. Ca concentrations increased under both stresses in the brain, eye, liver and spleen, and decreased in the intestine and ovary. Br concentrations of the organs largely changed in the case of salty water breeding. Micro-beam scanning PIXE provided elemental mapping of thin section of Medaka eye with STIM imaging.

In the criticality accident in Tokai-mura on 30 September 1999, two workers received especially high dose of neutrons and GAMMA-rays over their bodies. We measured the activities of neutron-induced BETA-emitters in the hair and bone of the workers to estimate the distribution of neutron fluence in the whole body. The measurement of 32P in hair samples taken from the head and pubis shows that both workers received higher doses of irradiation to the frontal side of their trunks than to the head. For a more detailed mapping of neutron fluence in the body, the measurements of 32P and 45Ca in bone were very effective. The results of bone analyses show that one worker (worker A) received a higher dose of neutrons at the frontal right side of the trunk, and that the dose decreased with the distance from the central part of the body. The other (worker B), seems to have gotten a higher dose of irradiation in the face, hands and waist. The 45Ca concentration ratio of worker B to worker A in the iliac bone agrees not only with the 32P concentration ratio in the pubic hair, but also with the ratio of the estimated average doses for the whole body from lymphocyte number, chromosome abbreviation and 24Na activity in the blood. This suggests that the dose to the abdomen could contribute mainly to the estimation of the average dose from the parameters in the blood. The analyses of BETA-emitters in hair and bone gave us valuable information for the estimation of the dose received by particular organs, which are critical for the health conditions of the workers.

Concentrations of radionuclides in blood, urine, vomit and hair samples from three heavily exposed patients were determined by gamma-spectrometry. Activation products such as 24Na, 42K and 82Br were identified in these materials. The radionuclide of the highest activity observed in biological material was 24Na, e. g. the concentrations of this nuclide in the blood samples from the three patients at the accident time were 169, 92 and 23 Bq ml^-1^. Concentrations of the stable Na in the same samples were determined by ICP-AES to obtain specific activities (concentration ratio between the produced 24Na and stable 23Na). The specific activities of 24Na obtained for the three patients through the blood analysis were 8.24*10^4^, 4.34*10^4^ and 1.23*10^4^Bq24Na/g23Na, respectively. Based on these values, neutron fluences for the three patients were estimated to be 5.7*10^11^, 3.0*10^11^ and 0.85 *10^11^ cm^-2^, respectively. Absorbed doses for three patients due to neutrons were estimated to be 5.4, 2.9 and 0.81Gy, those due to gamma-rays 8.5-13, 4.5-6.9 and 1.3-2.0Gy, respectively.

Micro-PIXE and inductively coupled plasma mass spectrometry (ICP-MS) were applied to elemental distribution analyses in plant root apex which is composed of various types of tissues and cells in different developmental stages. ICP-MS was so sensitive that a large number of elements including Na, Mg, P, S, K, Ca, Mn, Fe, Cu, Zn, Se, Rb, Sr and Cs could be determined quantitatively. These fourteen elements included almost all the essential elements for plant growth. Only a rough estimation, however, could be obtained by ICP-MS for the elemental distribution at the tissue level, by analyzing sections from the root apex. On the other hand, micro-PIXE was effective for detailed mappings of elemental distributions. The images of elemental distributions were obtained for Na, Mg, P, S, K, Ca, Mn, Fe and Zn, corresponding to the microscopic images of the root structures. The localizations of P, K and Zn in some tissues were observed by the mappings. These results indicated that micro-PIXE and ICP-MS have different, but complementary abilities for the investigation of elemental distributions in plant tissues.

10th International Conference on Nuclear Microprobe Technology and Applications

The Single Particle Irradiation to Cells (SPICE) facility has been constructed for biological cell irradiation, with the ability to deliver exactly defined numbers of ions into a small region within the area of an individual living cell. The SPICE is able to provide 3.4 MeV proton and 5.1 MeV alpha particle microbeams using a mono-bloc triplet quadrupole lens (Q lens), which is located just before the beam exit. We are currently adopting a scintillation counter that detects ions after passing through a biological cell, and a pair of electrostatic beam deflecting plates to realize single-ion irradiation. The output signal of the counter is fed to a computer-based scaler, and then a high voltage is applied for the deflecting plates to deflect the beam, once a defined number of protons has detected. The dosage precision of the single particle irradiation system has been tested for 3.4 MeV protons using 90 um thick CR-39 detector. The statistics of the etched pits number on the CR-39 has demonstrated that the single-ion irradiation system is capable of quantitative irradiation with the efficiency (the probability of which the number of traversal ion is equal to the preset value) measured to be 95.1%, ICNMTA2006

At National Institute of Radiological Sciences (NIRS), we constructed a microbeam system in 2003, named Single Particle Irradiation to Cell, SPICE. From the beginning of 2005, we redesigned it to improve the stability of the optical alignment of the system, and obtained an ensured reduction rate of the beam size proportional to the openness of the objective slit in the vertical line. As a result, SPICE is now capable of producing a beam size of approximately 10 micro meter diameter, and the numbers of particles are controllable to an intensity as low as single particles per second, and single particle irradiation has been succeeded. Moreover, these conditions can be easily reproduced with a routine everyday procedure. We describe in detail the modifications of the beam line and results indicating the improvements. In addition, the result of our first biological experiments is shown., 10th International Conference on Nuclear Microprobe Technology and Applications

Reproductive processes are particularly radiosensitive in plant development, which was clearly illustrated in reduction of seed formation in native coniferous plants around Chernobyl after the nuclear accident. For the purpose to investigate the effects of ionizing radiation on embryonic formation in coniferous plants, we used an embryo-derived embryogenic cell culture of a Japanese native coniferous plant, Japanese cedar (Cryptomeria japonica). The cells were so radiosensitive that most of the cells died by acute X-ray irradiation of 0.5 Gy. The cell death was characteristic of nuclear DNA fragmentation, which is typically observed in apoptosis in mammalian cells. The apoptosis-like cell did not develop in vegetative tissues, i.e. meristematic cells, after X-ray irradiation, and considered to be peculiar to embryogenic cells. Development of cell death in the embryogenic cells was suppressed by inhibitors against MAPkinases, which was activated two hours after X ray irradiation of the cells. The results indicate that the embryogenic cells develop apoptosis-like programmed cell death, which should be mediated by signal transduction through MAPkinases. The abortion of embryogenic cells may work to prevent transmission of radiation-induced genetic damages to the descendants., 日本放射線影響学会大４８回大会

In the environmental pollution studies, it is very important to detect not only pollutants but also changes induced in organisms in the environment with various environmental stresses such as heavy metal toxicity, radiation and agricultural chemicals. In the latter, monitoring is carried out using biological indicators to find out the changes, which have wide spectra from visible like deformity of the body to invisible such as changes in some enzyme activities [1,2]. Changes of the balance of essential elements could occur in organisms to deal with the stresses. If we detect an elemental balance shift, we may see the environmental pollution in its early stages. Moreover, in the actual environment, combined effects, additive or reductive with coexistent elements or other stresses, is an important subject for investigation. Therefore, measurement of many elements in the biological indicators simultaneously and determination of the distribution in the organisms are useful in clarifying the action of pollutants at sublethal levels. A small fresh water fish, Medaka can be used as one of the biological indicators for determination of water quality. In the National Institute of Radiological Sciences (NIRS), an inbred strain of Medaka Orizias laptipes was established and has been maintained for the research purposes. Since the genetic background of inbred animals is almost uniform, the individual deviation among animals is very small. This characteristic is very useful to investigate the physiological effects of environmental stresses. We have continued to investigate the balance shift of essential elements induced in the bodies of Medaka by several stresses. In this paper, elemental content in various organs of the X-ray irradiated fish determined by PIXE method are reported in comparison with that of the control fish to observe the effect of the X-rays. Body size of Medaka is about 3 cm long, and the internal organs are very small (about 1 mm on average). PIXE is the most suitable tool for this subject owing to its high sensitivity to detect elements and capability to analyze many elements in small samples simultaneously. One of the purposes of this study is to show the usefulness of PIXE method in determination of the elemental balance shift. The fishes were irradiated with X-ray in a plastic dish containing 5 mm depth of water using X-ray irradiation equipment (PANTAK-320S) at 200kV and 20mA. The dose rate was 224R/min and the total dose was 17Gy. The LD50/30 (50% Lethal Dose within 30 days) of this fish is 20Gy [3]. The X-ray irradiation did not induce any stressful behavior in this experimental period, about 3 weeks. After the X-ray irradiation, on the 2nd day, the 9th day and the 16th day, fishes were dissected and essential elements such as P, S, Ca, Mn, Fe, Cu and Zn in liver, gall bladder, kidney, spleen, heart, gill and brain in the fish were measured by PIXE method. And the contents in each organ were compared with those of the control fish to determine the effect of the stresses. Just after the X-ray irradiation, various changes of the elemental contents were observed depending on the organs. Brain showed less change of metal balance comparing to the other organs. Increases of P and Fe were observed in many organs. On the contrary, S showed the decreasing tendency. Recovery from the stress loading was also observed during 16 days. The result will be reported in this paper., Asia-Pasific Symposium on Radiochemistry-05

Workshop on Accelerator Operation 2005

Behaviour of radionuclides in the environment and organisms has been investigated to evaluate the radiation effect on human using stable isotopes using PIXE analysis at the PASTA facilities in the NIRS. Since some of the environmental monitoring samples are in the liquid state, pre-treatment of the samples such as filtration, drying and solidification are necessary prior to the PIXE analysis. During sample preparation process, there may be loss of element due to sublimation or evaporation that must be taken care for quantitative analysis. To avoid such problems, we have developed a suitable dropletPIXE system. It is based on the following points,(i) development of equipment with a good stability to supply a droplet of good reproducibility, (ii) optimisation of all equipments that includes a stable beam line (proton, 2.8MeV) and (iii) to evaluate irradiation dose for quantitative analysis. It will be advantageous to many researchers since it is very simple and save time during the sample preparation. However, there are some disadvantages in the detection range compared to conventional PIXE. The droplet-PIXE system has been applied to a few case studies. Limits of detection with or without any chemical preparation and its superiority or advantages over other PIXE system will be discussed in this paper. Application of the droplet-PIXE system can be expanded in future to other possibilities., 5th International Symposium on BioPIXE

The prostate is an accessory sex organ that secretes is an essential component of semen. High levels of Zn are found both in the prostate and its secretion. In the present study, the effects of environmental stress on zinc levels in the prostate were examined in Wistar male rats exposed to tributyltin chloride (TBTC), an environmental toxicant, by inductively coupled argon plasma mass spectrometry (ICP-MS) for determination of Zn concentration in lobe-dissectioned specimens and micro-PIXE analysis for determination of site-specific distribution of Zn in prostatic sections. A single oraly administration of TBTC to rats at a dose of 90 umol/kg resulted at 14 days later in a decrease in the Zn level in the dorsolateral prostate but not the ventral prostate. The TBTC did not affect the weight of the prostate tissue. Micro-PIXE imaging found Zn both in the lumen and the epithelium of the lateral prostatic tubules. PIXE spot analysis revealed that the epithelium of the control rat contained levels of Zn 4-fold higher than in the lumen and that Zn in the epithelium decreased selectively after TBTC exposure., BioPIXE5

第9回核マイクロプローブ技術と応用に関する国際会議

The 3rd International Symposium on Future Medical Engineering based on Bio-nanotechnology, Advanced Technologies in Functional Biomedical Imaging

National Institute of Radiological Sciences (NIRS) was established in 1957 as a special research institute for research and medical application of radiation, attached to the Science and Technology Agency of Japan. In 1961, NIRS started to use a Van de Graff accelerator (Model KN3000, High Voltage Engineering) for PIXE (Particle Induced X-ray Emission) analysis that was operated as a device for pre-tumor therapy with neutron and finally discarded in 1997. In March 1999, an electrostatic accelerator, HVEE Tandetron, was installed in the Electrostatic Accelerator Building for PIXE analysis. PIXE analysis is a trace analytical method, which has the advantage of simultaneous determination of elemental concentrations in a small specimen without any chemical separation by measuring characteristic X-rays of elements induced by accelerated charged nuclear particles such as protons. [1] In this paper, characteristics of the PIXE system and the new microbeam irradiation facility, Single Particle Irradiation System to Cell (SPICE), which is introduced to our Tandem accelerator are described., The 3rd International Symposium on Future Medical Engineering based on BIO-nanotechnology

International Symposium on Radioecology and Environmental Dosimetry

Among plant species, coniferous plants are particularly sensitive to ionizing radiation. We examined the effects of X-ray irradiation on cultured cells of Japanese cedar. Cell death in the cultured cells was increased drastically by X-ray irradiation at 5 Gy, which is as low as the dose inducing radiosensitive programmed cell death, i.e. apoptosis, in mammalian cells. The advancement of cell death in the Japanese cedar cells was accompanied by nuclear DNA fragmentation, which is typically observed both in apoptosis of mammalian cells and in hypersensitive programmed cell death observed in plant cells exposed to various environmental stresses. The results suggested that radiosensitive cell death should be involved in the susceptibility of coniferous plants to ionizing irradiation, and furthermore, this death should be a kind of programmed cell death which has a similarity to apoptosis in mammalian cells., International Conference on Protection of the Environment from the Effects of Ionizing Radiation

12th International Congress of Radiation Research

The scanning microbeam PIXE(Particle Induced X-ray Emission) analysis allows identifying the several surface elements and taking the high-resolution elemental maps of the specimen at a time, by using the narrow beam downed the size to 1um and the maximum scanning area of 2mm square. We are applying this system to the elements and the structure analysis for bio-cells and environmental specimens. The most important procedure to obtain the high-resolution maps is increasing spatial resolution of the micorbeam. We diagnose the resolution by using Scanning Transmission Ion Microscopy (STIM) and PIXE images of the 12.5um pitch copper mesh. In this workshop, we introduce our experiences of the alignment of the microbeam system., The 4th Workshop on Accelerator Operation

In March 1999, a HVEE Tandetron was installed in the Electrostatic Accelerator Building of NIRS (National Institute of Radiological Sciences) for PIXE (Particle Induced X-ray Emission) analysis. The specifications of the Tandetron accelerator system operating at NIRS are as follows: The accelerating voltage is 0.4 to 1.7MV, and the maximum beam current is 500nA at 3.4MeV. The accelerator facility incorporates three beam lines for conventional, in-air and microbeam PIXE analysis. The scanning microbeam PIXE analysis line is based around an Oxford Microbeams OM2000 nuclear microscope end stage. This system provides the ability of multi-elemental mapping over sample areas up to 2 ｝ 2 mm area with spatial resolutions routinely at 1 ｝ 1 micrometres. The scheduled operation of this facility started in April 2000 and is controlled by the Division of Technical Service and Development. The result of beam resolution tests carried out in 2001 are as follows: For Scanning Transmission Ion Microscopy (STIM), the estimated beam size is 100 ｝ 200 nm, measured using a 2.6 MeV proton beam scanned over a 12.7 ?? repeat distance copper grid. For Particle Induced X-ray Analysis (PIXE) operation at 50 pA beam current the estimated best spot size is 0.4 ｝ 0.6 ??. The micro beam facility is being used for research into the elemental distribution of small biological samples such as biological cells and tissue., The 8th International Conferecce on Nuclear Microprobe Technology and Applocations

The 8 th International Conference on Nuclear Microprobe Technology and Applications

Regrettably, a criticality accident occurred at a uranium conversion facility in Tokai-mura, Ibaraki, Japan, on 30 September, 1999. Radioactivities of 32P in urine, blood and bone samples of the victims who were severely exposed to neutrons were measured. 32P was induced in their whole bodies at the moment of the first nuclear excursion by the reaction 31P (n,gamma) 32P and 32S (n, p) 32P. A realistic biokinetic model was assumed as the exchange of 32P between extracellular fluid compartment and soft tissue compartment occurs only through intracellular compartment, and the model was used for preliminary calculations. Some acute excretion of 32P, caused by decomposition or elution of tissues which occurred at the time of the accident, may have happened in the victims' bodies in the first few days. The working hypotheses in the present work should initiate renewed discussion of 32P biokinetics., Workshop on Internal Dosimetry of Radionuclides：Occupational, Public and Medical Exposure

On September 30, 1999 three workers were carrying out a purification procedure in the uranium conversion building of JCO Company Limited, Tokai-mura, which resulted in the criticality accident. They had mixed uranium oxide powder (enrichment of 235U: 18.8%) with nitric acid and were pouring the solution, by hand, into a precipitation tank. These procedures were not permitted legally. About 16 kg of U were added to the tank, causing the nuclear fission chain reaction to start (at 10:35). The three workers were heavily exposed to neutrons and gamma-rays produced by the fission event. They were transported by ambulance, at first to a local hospital, then by helicopter to the National Institute of Radiological Sciences (NIRS), Chiba, about 120 km from Tokai-mura, which is the tertiary care center for radiation injuries. Immediately after their arrival at NIRS, radiological surveys were performed for the three patients in addition to intensive medical care. We carried out analyses of activation products such as 24Na in biological samples collected from the three patients and estimated the radiation doses for them. In this paper, we have summarized our results on the radioactivity measurements and dose estimations based on 24Na (Muramatsu et al.; Ishigure et al. ). [from Introduction]

The 7 th International Conference on Nuclear Analytical Methods in the Life Science

The 7 th International Conference on Nuclear Analytical Methods in the Life Science

BioPIXE

An electrostatic accelerator, Tandetron (Model 4117MC, High Voltage Engineering Europe Co.) was installed in National Institute of Radiological Sciences (NIRS) for PIXE (Particle Induced X-ray Emission) analysis in 1999. The accelerating voltage is 0.4 to 1.7MV, and the maximum beam current is 5microA at 3.4MeV. This system has three beam ports for different types of PIXE analysis, conventional, micro-beam and in-air. Normal PIXE line has two types of X-ray detecting device, Si (Li) and CdZnTe detectors detectable for elements from Na (Z=11) to U (Z=92). Fifteen samples can semi automatically be measured at one time with the optical beam size from 0.5 to 2.0 mm at 100 nA of the beam current. A quadruple triplet magnet (Model OM2000, Oxford Micro beams, Ltd.) attached to the other beam port produces a proton micro-beam of the square shape less than 1micron x 1micron. Micro-beam scanning PIXE analysis is carried out with this beam at 50pA current and scanning area up to 2.0mm square. The in-air PIXE analysis is performed using the third beam port. In this paper, we introduce micro-PIXE scanning system showing the ability to draw elemental maps in a spatial resolution of about 1 µm with analyses of fish scale, fish otolith, crocus pollen and micro organisms. Fine ring structure of a fish scale was observed using elemental mapping with proton micro-beam scanning. Pollen was analyzed as one example of single cell to demonstrate the elemental distribution. Fish scale and otolith seem to be a kind of time recorder like tree rings. And the elemental composition reflects the living condition. Therefore, fish scale and otolith are possible to be used as a biological indicator., 3rd International Symposium on Nuclear Analytical Chemistry (NAC-III)